7/31/2013
 

Use Of CO2 Emission Rate Data to Derive
 

Achievable NSPS for Coal‐Fired Electric
 

Generating Units
 

Supporting Material for the July 31, 2013
 

Discussion with
 

Office of Management & Budget
 

Prepared by
 

J. Edward Cichanowicz and Michael C. Hein
 

Consultants to ACCCE
 

DISCUSSION OUTLINE

•	 Consider Full “Plate” of Reference Units

•	 Factors Affecting CO2 Emissions Rate

•	 Variability in CO2 Emissions

•	 Achievable CO2 Emission Rates

•	 Ultra‐Supercritical Boiler (AEP Turk) CO2

Emission Rate Variability

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55 “NEW” COAL‐FIRED UNITS COMMENCED

OPERATION AFTER JAN 1, 2007

22 Units 55

Units

Fuel: ‐6

Capacity: ‐20

Cooling: ‐2

Data Available: ‐7

Subcritical PC

‐8 PRB

‐2 E. Bit

Supercritical PC

‐2 PRB

‐2 E. Bit

‐2 Texas Lignite

EPA Reference f ( )+1

‐Remove Bull Run

‐Keep Zimmer

‐Weston, W Scott

included

Subcritical FBC

‐2 Texas lignite (+1)

‐1 E. Bit

Cichanowicz, Hein OMB Discussion: July 31, 2013 3

17 “PC” UNITS FIRING PRB, E. BIT

Cichanowicz, Hein OMB Discussion: July 31, 2013 4

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WHAT AFFECTS CO2 EMISSION RATE?

• Steam Conditions (Supercritical vs. Subcritical)

• Heat Rejection Method

– Once‐thru vs. cooling towers (wet, dry, hybrid)

– Cooling towers: ambient temperature, humidity

• Coal Composition (Moisture, Acid Dewpoint)

• Operating Duty

– First year can be atypical

– % maximum capacity (excess air, steam turbine)

– Cycling vs. steady state

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CO2 EMISSION RATE: EFFECT OF LOAD

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CAPTURE, REFLECT CO2 VARIABILITY?

• Statistically Treat Data from Many Units

• Example: 1997 NOx NSPS

– Limited data: Use hourly data to calculate block,

rolling averages for units with NOx controls

– Statistical method1: EPA found 30‐day NOx limits

attained with infrequent “failure” (1%, 1/yr; 1/10 yrs)

• Parallel for 2013 CO2 NSPS

– Limited data: annual basis

– Same statistical method can derive annual emissions 1 New Source Performance Standards, Subpart Da – Technical Support for Proposed Revisions to NOx Standard,

EPA‐453/R‐94‐012, June 1997

Cichanowicz, Hein OMB Discussion: July 31, 2013 7

ANALYTICAL APPROACH
 

• Eliminate 1st Year ‐ Atypical (1 to 11 months)

• “Pool” Data From Exhibit 6 in Categories

• Explore Key Variables

– Fuel type (PRB vs. E. Bit vs. lignite)

– Boiler type (PC subcrit, FBC subcrit, PC supercrit)

• Focus on Three Categories

– Subcritical boilers: subbit/bit

– Supercritical boilers: subbit/bit

– Fluid bed, “PC” boilers: lignite

Cichanowicz, Hein OMB Discussion: July 31, 2013 8

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CUMULATIVE DISTRIBUTION:

DAILY CO2 DATA (w/o 1st Yr)

Cichanowicz, Hein OMB Discussion: July 31, 2013 9

ANNUAL EMISSION RATE PER

DAILY CO2 DATA: TWO “FAILURE” RATES

Cichanowicz, Hein OMB Discussion: July 31, 2013 10

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Cichanowicz, Hein OMB Discussion: July 31, 2013 11

TURK ULTRA‐SUPERCRITICAL BOILER:

CO2 EMISSIONS RATE VARIABILITY

OBSERVATIONS: CO2 EMISSION DATA

• 22 New Units Since 2007 Suggest

– Subcritical: 2,080 lbs/MWh

– Lignite: 2,150 lbs/ MWh

– Supercritical: 1,915 lbs/MWh

• Limited Data from Ultra‐Supercritical Units

– Thermal efficiency (LHV‐Basis) typically reported

– Coal composition to convert to HHV‐basis

– Operating conditions unknown

• Hourly CO2, MWh Data for Realistic Analysis

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Questions?

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